Water and Effluent Treatment Magazine
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10 WET NEWS APRIL 2014 Screw blowers put the air into anaerobic treatment PROJECT SPECS • Provide a constant, reliable supply of air to 480mbar • Investigate the possibility of install- ing new generation high efficiency screw type blowers • Replace lobe blower with a low-pres- sure, oil-free rotary screw blower ONSITE Energy efficiency WHATEVER THE PE PIPE DIAMETER WHATEVER THE COIL LENGTH* There's a Steve Vick International Trailer for its safe, easy transportation, storage and dispensing. *From 40mm diameter pipe right up to 180mm diameter and coil lengths up to 500 metres. Please contact us for more information: Steve Vick International Ltd Treenwood Industrial Estate Bradford-on-Avon, Wiltshire BA15 2AU Phone: +44 (0)1225 864 864 info@stevevick.com www.stevevick.com Making the difference in Water Treatment sera ProDos UK Ltd. Axon 2, Commerce Road, Lynchwood, Peterborough PE2 6LR Phone: +44 1733 396040 Fax: +44 1733 396050 Email: sales.uk@sera-web.com www.sera-web.com For more than 65 years sera products have represented the highest measure of quality, safety and reliability in the treatment of drinking water, process water and wastewater. n Dosing and feeding pumps n Dosing systems and disinfection systems n Process measuring and control technology n Fittings and accessories n Extensive pre- and after-sales service We don't just promise, we do! • When Northumbrian Water needed to replace a lobe type blower, it turned to Atlas Copco for help. Following comparison tests, it opted to use Atlas Copco's new generation of high efficiency screw type blowers. 10 WET NEWS APRIL 2014 Northumbrian Water wanted to minimise service costs at its Newton Aycliffe sewage treatment works Screw blowers put the air into anaerobic treatment N orthumbrian Water, a leading provider of water and sewerage services in the North-east of England, needs a constant, reliable sup- ply of air in the region of 480mbar for aerobic treatment of wastewater at its site in New- ton Aycliffe, County Durham. This process uses bacteria to break up waste particles and re- quires large amounts of air to be blown into the aeration tanks to maintain the desired level of dissolved oxygen within the wastewater containment sys- tem – a biological process that typically utilises up to 70% of the energy consumed on site. As a result, the company has opted to use Atlas Copco screw blower technology to help reduce energy consumption and minimise service costs at the sewage treatment works in Newton Aycliffe, County Durham. There is a changing perspec- tive within the water industry that the widely-used lobe blower design principle no longer meets the needs of today's low carbon economy and that operators can benefit substantially from energy savings through the replacement of conventional lobe equipment with innovative screw technology. New generation Such was the experience of Northumbrian Water, whose aeration air supply was Wedeco Spektron UV Wedeco LBX UV Reactors Sanitaire Aeration Grids Hydroejectors & Radial Aerators Flygt Jet Aerators & Mixers Flygt Mixers AVAILABLE FROM XYLEM WATER TREATMENT 24/7 HIRE RAPID BESPOKE DESIGN SOLUTIONS DIRECT FROM THE MANUFACTURER FOR ULTIMATE PEACE OF MIND • Cost effective temporary treatment installations • Plant refurbishments | Repairs | Seasonal Overloads Drought Alleviation • Portable containerised systems available for larger projects • Planned, bespoke and reactive maintenance solutions • PLUS monitoring, control and analytical equipment also available 0845 707 8012 rental@flygt.co.uk | www.xylemwatersolutions.com/uk flygt_sanitaire_wedeco treatmentl advert rev C_Layout 1 28/02/2014 17:10 Page 1 originally delivered to the site by four lobe type blowers. How- ever, when one of these units started to develop reliability issues, the opportunity was taken to investigate the possi- bility of installing one of the new generation of high effi- ciency screw type blowers which, compared to standard lobe type machines, offer poten- tial savings of up to 30% in energy consumption. Northumbrian Water decided to replace one lobe blower with the Atlas Copco ZS screw blower technology. On completion of the installation of the new ZS blower, Northum- brian Water carried out a com- parison performance test between the existing lobe blow- ers and Atlas Copco's ZS technology. Data from air flow meters and power monitors was put into the site's PLC / SCADA sys- tem to calculate the specific power of all four air blowers. The calculated values of air pro- duction were averaged over a 12-hour period. In order to compare like for like, the ZS unit was compared with the performance of the other blowers at the same time on the following or preceding days during similar weather, flow and biological load conditions. It revealed that the existing lobe blower used around 19% more power for the same output. Based on these test results and continuous relia- bility issues with the lobe blow- ers it was decided to replace a second lobe blower with an Atlas Copco ZS90-VSD, low- pressure, oil-free rotary screw blower. The blower unit comprises a complete package based on a simple internal principle: preci- sion timing gears maintain minute clearances between two intermeshing dry screw ele- ments that never touch. No lubrication is required in the compression space and spe- cially designed seals prevent any rotor bearing oil from entering the compression chamber. Intake air is compressed between the rotors and their "I would say that the proof is in the pudding and given that NWL have chosen to replace all blowers with the Atlas Copco units speaks volumes" Alan Harle, Northumbrian Water ►